In work related to the Early Pregnancy Study we identified factors related to the timing of implantation relative to ovulation, i.e. conception. This duration was regarded as a useful endpoint because of previous work that had found it predicted the risk of very early pregnancy loss, in that durations longer than 10 days were likely to be associated with loss. We are now preparing a paper related to factors that are related to the length of human pregnancy. We found that certain very early pregnancy factors are predictive of the length of gestation. This paper is about to be submitted.